Key Deadlines IT Admins Need to Know for Microsoft 365 Products and Features

Microsoft will officially drop support for Windows 10 on October 14, 2025. Additionally, the company has announced plans to retire several key Microsoft 365 features and products by the end of this year, urging customers to prepare for these upcoming changes (via AdminDroid).

First off, Microsoft has detailed some important changes coming to the Teams PowerShell cmdlets. Later this month, Microsoft plans to deprecate Get-CsDialPlan cmdlet. The company will also retire DialPlan attribute from Get-CsOnlineUser and LocationProfile attribute from Get-CsUserPolicyAssignment cmdlet. Microsoft recommends customers to use the Get-CsEffectiveTenantDialPlan cmdlet instead.

Exchange Online Legacy Tokens

Microsoft will turn off Exchange Online Legacy Tokens across Microsoft 365 tenants in February 2025. However, administrators will have the temporary option to enable them via PowerShell. Microsoft will remove the option to re-enable Legacy Tokens in June. However, Exchange Online Legacy Tokens will be turned off for all tenants in October.

It’s important to note that the depreciation of Exchange Online legacy Tokens will impact old Outlook add-ins, which help users manage emails, appointments, tasks, and other features. Microsoft urges organizations to migrate Outlook add-ins to use Entra ID tokens through Nested App Authentication (NAA) and Microsoft Graph.

RBAC application impersonation role in Exchange Online

Additionally, Microsoft will retire the RBAC application impersonation role in Exchange Online due to security concerns next month. This role is used to grant service applications access to multiple mailboxes. Customers can use Role-Based Access Control for applications accessing mailboxes. Microsoft strongly recommends organizations to migrate apps to Microsoft Graph for accessing Exchange Online data.

Azure AD and MSOnline Powershell modules

Microsoft will drop support for the Azure AD and MSOnline Powershell modules at the end of March. Administrators are advised to identify all PowerShell scripts that use the legacy modules and upgrade them to Microsoft Graph PowerShell.

Domain isolated web parts in SharePoint Framework

Microsoft will drop support for domain isolated web parts in SharePoint Framework on April 2. This feature will initially be disabled for new tenants, followed by existing tenants on April 2, 2026.

Domain isolated web parts feature allows developers to create web parts running in a separate domain from the host page. However, running web parts in a dedicated domain introduced performance challenges that impacted the overall user experience. It’s recommended to migrate domain isolated web parts to regular web parts.

Classic Microsoft Teams

Microsoft will retire the classic Teams desktop app for all users on July 1. Users will need to switch to the new Microsoft Teams client or the Teams web app instead. Later this year, Microsoft will deprecate Office 365 connectors within Microsoft Teams. These connectors allow users to receive updates and notifications from various third-party services directly into a Teams channel.

Basic Auth for Client Submission (SMTP AUTH) in Exchange Online and more

In September, Microsoft will end support for basic authentication for client submission in Exchange Online. Organizations should transition to OAuth with Client Submission (SMTP AUTH) as soon as possible. Moreover, IT admins will no longer be able to manage authentication methods via legacy MFA and self-service password reset (SSPR) policies. Microsoft urges migration to Authentication methods policy in Microsoft Entra.

In October, Office 2016 and Office 2019 will reach end of support on October 14, and customers would need to switch to Microsoft 365 Apps to receive support and updates. Furthermore, Microsoft 365 apps will no longer be supported on Windows Server 2016 and Windows Server 2019.

Lastly, Microsoft is getting ready to retire Viva Goals on December 31, 2025. Administrators should disable auto-renewal in the Microsoft 365 Admin Center and consider exporting data through API, Excel, and PowerPoint.